Over the life of a vehicle, worn brake pads of disc-brake assemblies will need to be replaced a number of times. This is usually accomplished by first spreading the worn brake pads, forcing each caliper piston into its piston housing, and then replacing the worn pads with new pads.
Hand tools for spreading vehicle brake pads and for compressing caliper pistons are know. One such tool is described in the specification of U.S. Pat. No. 6,874,217 and an improvement to that tool is described in the specification of U.S. Pat. No. 7,076,850. Each described tool has a body, a handle extending from the body, a hand-operable lever pivotally connected to the body, a shaft extending through the body and movable between forward and reverse directions relative to the body, a movable load applying member mounted to the shaft for applying a load when moved by the shaft into engagement with a brake pad, piston or caliper casting, a fixed load applying member fixed in position relative to the body for applying a load to a brake pad, piston or caliper casting, a shaft drive mechanism operatively connected to the shaft and lever for incrementally advancing the shaft in the forward direction, and a shaft release mechanism that when actuated allows the shaft to be moved in the reverse direction so as to allow disengagement of the load applying members from the brake assembly.
A disadvantage of each above mentioned tool is that it can only be used for the one caliper unit type that it was designed for. Yet another disadvantage is that, when the tool is under heavy load, a short release lever of the shaft release mechanism can be difficult to actuate so as to allow the shaft to be moved in the reverse direction.